Organic light emitting device

ABSTRACT

An organic light emitting device including an anode; a hole transport region on the anode; an emission layer on the hole transport region; an electron transport region on the emission layer; and a cathode on the electron transport region, wherein the hole transport region includes: a first hole transport layer including a first hole transport material represented by the following Formula 1 or a second hole transport material represented by the following Formula 2; and a second hole transport layer on the first hole transport layer, the second hole transport layer including a third hole transport material represented by the following Formula 3 or a fourth hole transport material represented by the following Formula 4:

CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2016-0038593, filed on Mar. 30, 2016,in the Korean Intellectual Property Office, and entitled: “Organic LightEmitting Device,” is incorporated by reference herein in its entirety.

BACKGROUND 1. Field

Embodiments relate to an organic light emitting device.

2. Description of the Related Art

Recently, the development of an organic light emitting display device asan image display device is being actively conducted. Different from aliquid crystal display device, the organic light emitting display deviceis a self-luminescent display device in which holes and electronsinjected from an anode and a cathode recombine in an emission layer, anda luminescent material including an organic compound in the emissionlayer emits light to accomplish display.

As an organic light emitting device, an organic device may include,e.g., an anode, a hole transport region disposed on the anode, anemission layer disposed on the hole transport region, an electrontransport region disposed on the emission layer, and a cathode disposedon the electron transport region. Holes are injected from the anode, andthe injected holes move and are injected into the emission layer.Meanwhile, electrons are injected from the cathode, and the injectedelectrons move and are injected into the emission layer. The holes andelectrons injected into the emission layer recombine to generateexcitors in the emission layer. The organic light emitting device emitslight using light generated by the radiation deactivation of theexcitons. In addition, the organic light emitting device is not limitedto the above-described configuration; and various modifications may bepossible.

SUMMARY

Embodiments are directed to an organic light emitting device.

The embodiments may be realized by providing an organic light emittingdevice including an anode; a hole transport region on the anode; anemission layer on the hole transport region; an electron transportregion on the emission layer; and a cathode on the electron transportregion, wherein the hole transport region includes: a first holetransport layer including a first hole transport material represented bythe following Formula 1 or a second hole transport material representedby the following Formula 2; and a second hole transport layer on thefirst hole transport layer, the second hole transport layer including athird hole transport material represented by the following Formula 3 ora fourth hole transport material represented by the following Formula 4:

wherein, in Formulae 1, 2, 3 and 4, Ar₁, Ar₂, Ar₃, Ar₄, Ar₅, Ar₆, Ar₇,and Ar₈ are each independently a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring carbon atoms, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted silyl group, a halogen atom, a deuterium atom, or ahydrogen atom, X is a direct linkage or CR₁₄R₁₅, R₁, R₂, R₃, R₄, R₅, R₆,R₇, R₈, R₉, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄ and R₁₅ are each independently asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring carbon atoms, a substituted or unsubstituted alkyl group having 1to 20 carbon atoms, a substituted or unsubstituted silyl group, ahalogen atom, a deuterium atom, or a hydrogen atom, L₁ and L₂ are eachindependently a direct linkage, a substituted or unsubstituted alkylgroup having 6 to 30 carbon atoms, a substituted or unsubstitutedarylene group having 6 to 30 ring carbon atoms, or a substituted orunsubstituted heteroarylene group having 5 to 30 ring carbon atoms, a,b, and c are each independently an integer of 0 to 4, d is an integer of0 to 3, and e is an integer of 0 to 5, in the case where e is an integerof 2 to 5, adjacent ones of R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, R₉, R₁₀,R₁₁, R₁₂, R₁₃, R₁₄ and R₁₅ are separate or are bound form a ring.

The emission layer may include an emission material containing a donorand an acceptor, the emission material being a thermally activateddelayed fluorescence material.

The first hole transport layer may include the first hole transportmaterial represented by Formula 1, and Ar₁ and Ar₂ in Formula 1 mayinclude a substituted or unsubstituted phenyl group, a substituted orunsubstituted biphenyl group, a substituted or unsubstituted naphthylgroup, a substituted or unsubstituted fluorenyl group, or a substitutedor unsubstituted acridine group.

The first hole transport layer may include the first hole transportmaterial represented by Formula 1, and L₁ in Formula 1 may include asubstituted or unsubstituted phenylene group, a substituted orunsubstituted divalent biphenyl group, or a substituted or unsubstitutedfluorenylene group.

The first hole transport layer may include the first hole transportmaterial represented by Formula 1, and the first hole transport materialmay include one of the, following Compounds 1-1 to 1-20:

The first hole transport layer may include the second hole transportmaterial represented by Formula 2, and Ar₃ and Ar₄ in Formula 2 may bebound to form a ring.

The first hole transport layer may include the second hole transportmaterial represented by Formula 2, and Ar₃ and Ar₄ in Formula 2 mayinclude a substituted or unsubstituted phenyl group, a substituted orunsubstituted biphenyl group, a substituted or unsubstituted naphthylgroup, a substituted or unsubstituted fluorenyl group, or a substitutedor unsubstituted spirobifluorenyl group.

The first hole transport layer may include the second hole transportmaterial represented by Formula 2, and Ar₅ in Formula 2 may include asubstituted or unsubstituted phenyl group, a substituted orunsubstituted dibenzofuran group, or a substituted or unsubstitutedpyridine group.

The first hole transport layer may include the second hole transportmaterial represented by Formula 2, and L₂ in Formula 2 may include adirect linkage, a substituted or unsubstituted phenylene group, asubstituted or unsubstituted divalent biphenyl group, or a substitutedor unsubstituted fluorenylene group.

The first hole transport layer may include the second hole transportmaterial represented by Formula 2, and the second hole transportmaterial may include one of the following Compounds 2-1 to 2-20:

The second hole transport layer may include the third hole transportmaterial represented by Formula 3, and Ar₆ and Ar₇ in Formula 3 mayinclude a substituted or unsubstituted phenyl group, a substituted orunsubstituted biphenyl group, a substituted or unsubstituted naphthylgroup, a substituted or unsubstituted dibenzofuran group, or asubstituted or unsubstituted dibenzothiophene group.

The second hole transport layer may include the third hole transportmaterial represented by Formula 3, and R₅ in Formula 3 may include asubstituted or unsubstituted phenyl group, a substituted orunsubstituted biphenyl group, a substituted or unsubstituted naphthylgroup, a substituted or unsubstituted fluorenyl group, a substituted orunsubstituted dibenzofuran group, or a substituted or unsubstitutedbenzo[def]carbazole group.

The second hole transport layer may include the third hole transportmaterial represented by Formula 3, and the third hole transport materialmay include one of the following Compounds 3-1 to 3-20:

The second hole transport layer may include the fourth hole transportmaterial represented by Formula 4, and Ar₈ in Formula 4 may combine withat least one of R₆ or R₁₃ to form a ring.

The second hole transport layer may include the fourth hole transportmaterial represented by Formula 4, and R₉ and R₁₀ in Formula 4 maycombine to form a ring that includes X.

The second hole transport layer may include the fourth hole transportmaterial represented by Formula 4, and Ar₈ in Formula 4 may include asubstituted or unsubstituted phenyl group, a substituted orunsubstituted biphenyl group, or a substituted or unsubstitutedcarbazole group.

The second hole transport layer may include the fourth hole transportmaterial represented by Formula 4, and R₆, R₇, R₈, R₉, R₁₀, R₁₁, R₁₂,R₁₃, R₁₄ and R₁₅ in Formula 4 may include a substituted or unsubstitutedphenyl group, a substituted or unsubstituted naphthyl group, substitutedor unsubstituted carbazole group, a substituted or unsubstitutedbenzo[def]carbazole group, a substituted or unsubstituted fluorenylgroup, a substituted or unsubstituted dibenzofuran group, a substitutedor unsubstituted triphenylene group, a substituted or unsubstitutedphenanthrene group, or a substituted or unsubstituted dibenzosilolegroup.

The second hole transport layer may include the fourth hole transportmaterial represented by Formula 4, and the fourth hole transportmaterial may include one of the following Compounds 4-1 to 4-20:

The hole transport region may further include a hole injection layerbetween the anode and the first hole transport layer.

The electron transport region may include an electron transport layer;and an electron injection layer on the electron transport layer.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will be apparent to those of skill in the art by describing indetail exemplary embodiments with reference to the attached drawings inwhich:

FIG. 1 illustrates a schematic cross-sectional view of an organic lightemitting device according to an embodiment of the present disclosure;and

FIG. 2 illustrates a schematic cross-sectional view of an organic lightemitting device according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Example embodiments will now be described more fully hereinafter withreference to the accompanying drawings; however, they may be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey exemplary implementations to those skilled in the art.

Like reference numerals refer to like elements for explaining eachdrawing. In the drawings, the sizes of elements may be enlarged forclarity of the present disclosure. It will be understood that, althoughthe terms first, second, etc. may be used herein to describe variouselements, these elements should not be limited by these terms. Theseterms are only used to distinguish one element from another element. Forexample, a first element discussed below could be termed a secondelement, and similarly, a second element could be termed a firstelement. As used herein, the singular forms are intended to include theplural forms as well, unless the context clearly indicates otherwise.

It will be further understood that the terms “comprises,” “includes,”“including,” or “comprising,” when used in this specification, specifythe presence of stated features, numerals, steps, operations, elements,parts, or a combination thereof, but do not preclude the presence oraddition of one or more other features, numerals, steps, operations,elements, parts, or a combination thereof. It will also be understoodthat when a layer, a film, a region, a plate, etc. is referred to asbeing ‘on’ another part, it can be directly on the other part, orintervening layers may also be present. On the contrary, when a layer, afilm, a region, a plate, etc. is referred to as being ‘under’ anotherpart, it can be directly under the other part, or intervening layers mayalso be present. In addition, the term “or” is not an exclusive termsuch that “A or B” would include all combinations thereof, i.e., A, B,or A and B.

In the present disclosure, “substituted or unsubstituted” may meansubstituted with at least one substituent selected from deuterium,halogen, nitrile, nitro, amino, silyl, boron, phosphine oxide, alkyl,alkoxy, alkenyl, fluorenyl, aryl, and heterocycle or unsubstituted. Inaddition, each of the substituent illustrated above may be substitutedor unsubstituted. For example, biphenyl may be interpreted as aryl, orphenyl substituted or unsubstituted with phenyl.

In the present disclosure, the description of forming a ring bycombining or bonding adjacent groups with each other may mean forming asubstituted or unsubstituted hydrocarbon ring or a substituted orunsubstituted heterocycle by the combination of adjacent groups witheach other. The hydrocarbon ring may include an aliphatic hydrocarbonring and an aromatic hydrocarbon ring. The heterocycle may include analiphatic heterocycle and aromatic heterocycle. The hydrocarbon ring andheterocycle may be a monocycle or polycycle. In addition, the ringformed by combining adjacent groups may be connected with another ringto form a spiro structure.

In the present disclosure, the terms “an adjacent group” may mean asubstituent at an atom which is directly connected with another atom atwhich a corresponding substituent is substituted, another substituent atan atom at which a corresponding substituent is substituted, or asubstituent stereoscopically disposed at the nearest position to acorresponding substituent. For example, two methyl groups in1,2-dimethylbenzene may be interpreted as “adjacent groups”, and twoethyl groups in 1,1-diethylcyclopentene may be interpreted as “adjacentgroups”.

In the present disclosure, a halogen atom may include a fluorine atom, achlorine atom, a bromine atom, or an iodine atom.

In the present disclosure, the alkyl group may have a linear, branched,or cyclic shape. The carbon number of the alkyl group may be 1 to 30, 1to 20, 1 to 10, or 1 to 6. Examples of the alkyl group may includemethyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, t-butyl, i-butyl,2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, i-pentyl, neopentyl,t-pentyl, cyclopentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl,4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl,cyclohexyl, 4-methylcyclohexyl, 4-t-butylcyclohexyl, n-heptyl,1-methylheptyl, 2,2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl,n-octyl, t-octyl, 2-ethyloctyl, 2-butyloctyl, 2-hexyloctyl,3,7-dimethyloctyl, cyclooctyl, n-nonyl, n-decyl, adamantyl,2-ethyldecyl, 2-butyldecyl, 2-hexyldecyl, 2-octyldecyl, n-undecyl,n-dodecyl, 2-ethyldodecyl. 2-butyldodecyl, 2-hexyldodecyl,2-octyldodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl,2-ethylhexadecyl, 2-butylhexadecyl, 2-hexylhexadecyl, 2-octylhexadecyl,n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, 2-ethyl eicosyl,2-butyl eicosyl, 2-hexyl eicosyl, 2-octyl eicosyl, n-henicosyl,n-docosyl, n-tricosyl, n-tetracosyl, n-pentacosyl, n-hexacosyl,n-heptacosyl, n-octacosyl, n-nonacosyl, n-triacontyl, etc., withoutlimitation.

In the present disclosure, the aryl group may mean an optionalfunctional group or substituent derived from an aromatic hydrocarbonring. The aryl group may be monocyclic aryl or polycyclic aryl. Thecarbon number of the aryl group for forming a ring may be 6 to 30, or 6to 20. Examples of the aryl may include phenyl, naphthyl, fluorenyl,anthracenyl, phenanthryl, biphenyl, terphenyl, quaterphenyl,quinqphenyl, sexiphenyl, triphenylene, pyrenyl, benzofluoranthenyl,chrysenyl, etc., without limitation.

In the present disclosure, the fluorenyl group may be substituted, ortwo substituents may be combined with each other to form a Spirostructure.

In the present disclosure, the heteroaryl group may be heteroarylincluding at least one of O, N or S as a heteroatom. The carbon numberof the heteroaryl group for forming a ring may be 2 to 30, or 2 to 20.Examples of the heteroaryl group may include thiophene, furan, pyrrole,imidazole, thiazole, oxazole, oxadiazole, triazole, pyridyl, bipyridyl,pyrimidyl, triazine, triazole, acridyl, pyridazine, pyrazinyl,quinolinyl, quinazoline, quinoxalinyl, phenoxazyl, phthalazinyl, pyridopyrimidinyl, pyrido pyrazinyl, pyrazino pyrazinyl, isoquinoline, indole,carbazole, N-arylcarbazole, N-heteroaryl carbazole, N-alkyl carbazole,benzoxazole, benzoimidazole, benzothiazole, benzocarbazole,benzothiophene, dibenzothiophene, thienothiophene, benzofuranyl,phenanthroline, thiazolyl, isooxazolyl, oxadiazolyl, thiadiazolyl,benzothiazolyl, phenothiazinyl, dibenzofuranyl, etc., withoutlimitation.

In the present disclosure, the explanation on the aryl group may beapplied to the arylene group, except that the arylene group is adivalent group.

In the present disclosure, the silyl group may include alkyl silyl groupand aryl silyl group. Examples of the silyl group may includetrimethylsilyl, triethylsilyl, t-butyl dimethylsilyl, vinyldimethylsilyl, propyl dimethylsilyl, triphenylsilyl, diphenylsilyl,phenylsilyl, etc., without limitation.

In the present disclosure, the boron group may include alkyl boron groupand aryl boron group. Examples of the boron group may include trimethylboron, triethyl boron, t-butyl dimethyl boron, triphenyl boron, diphenylboron, phenyl boron, etc., without limitation.

In the present disclosure, the alkenyl group may be linear or branched.The carbon number is not specifically limited, however may be 2 to 30, 2to 20, or 2 to 10. Examples of the alkenyl group may include vinyl,1-butenyl, 1-pentenyl, 1,3-butadienyl aryl, styrenyl, stilbenyl, etc.,without limitation.

Hereinafter, the organic light emitting device according to anembodiment of the present disclosure will be explained.

FIG. 1 illustrates a schematic cross-sectional view of an organic lightemitting device according to an embodiment of the present disclosure.FIG. 2 illustrates a schematic cross-sectional view of an organic lightemitting device according to an embodiment of the present disclosure.

Referring to FIGS. 1 and 2, an organic light emitting device 10according to an embodiment of the present disclosure may include ananode AN, a hole transport region HTR, an emission layer EML, anelectron transport region ETR, and a cathode CAT.

The anode AN has conductivity. The anode AN may be a pixel electrode ora positive electrode. The anode AN may be a transmissive electrode, atransflective electrode, or a reflective electrode. In the case wherethe anode AN is the transmissive electrode, the anode AN may be formedusing a transparent metal oxide such as indium tin oxide (ITO), indiumzinc oxide (IZO), zinc oxide (ZnO), or indium tin zinc oxide (ITZO). Inthe case where the anode AN is the transflective electrode or reflectiveelectrode, the anode AN may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd,Ir, Cr, Li, Ca, LiF/Ca, LiF/Al, Mo, Ti, a compound thereof, or a mixturethereof (for example, a mixture of Ag and Mg). In an implementation, theanode AN may include a plurality of layers including a reflective layeror transflective layer formed using the above materials, and atransparent layer formed using ITO, IZO, ZnO, or ITZO.

The hole transport region HTR may be provided on the anode AN. The holetransport region HTR may include, e.g., a first hole transport layerHTL1 and a second hole transport layer HTL2 (e.g., different from thefirst hole transport layer). In an implementation, the hole transportregion HTR may further include at least one of a hole injection layerHIL, a hole buffer layer and an electron blocking layer. In animplementation, the thickness of the hole transport region HTR may be,e.g., from about 1,000 Åto about 1,500 Å. In an implementation, thethickness of the hole transport region HTR may be from about 100 Å toabout 10,000 Å, e.g., from about 100 Å to about 1,000 Å.

The hole transport region HTR may be formed using various methods,e.g.,a vacuum deposition method, a spin coating method, a cast method, aLangmuir-Blodgett (LB) method, an inkjet printing method, a laserprinting method, or a laser induced thermal imaging (LITI) method.

The hole injection layer HIL may include, e.g., a phthalocyaninecompound such as copper phthalocyanine;N,N′-diphenyl-N,N′-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4′-diamine(DNTPD), 4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine(m-MTDATA), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine (TDATA),4,4′,4″-tris{N-(2-naphthyl)-N-phenylamino}-triphenylamine (2-TNATA),poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS),polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), polyaniline/camphorsulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate)(PANI/PSS), N,N′-dinaphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB),triphenylamine-containing polyether ketone (TPAPEK),4-isopropyl-4′-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate,or the like.

In an implementation, the first hole transport layer HTL1 may include,e.g.. a first hole transport material represented by the followingFormula 1 or a second hole transport material represented by thefollowing Formula 2. The second hole transport layer HTL2 may beprovided on the first hole transport layer HTL1. In an implementation,the second hole transport layer HTL2 may include, e.g., a third holetransport material represented by the following Formula 3 or a fourthhole transport material represented by the following Formula 4.

Ar₁, Ar₂, Ar₃, Ar₄, Ar₅, Ar₆, Ar₇, and Ar₈ may each independently beselected from or include, e.g., a substituted or unsubstituted arylgroup having 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring carbon atoms, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted silyl group, a halogen atom, a deuterium atom, or ahydrogen atom.

X may be, e.g., a direct linkage or CR₁₄R₁₅.

R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, R₉, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄ and R₁₅ mayeach independently be selected from or include, e.g., a substituted orunsubstituted aryl group having 6 to 30 ring carbon atoms, a substitutedor unsubstituted heteroaryl group having 5 to 30 ring carbon atoms, asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms, asubstituted or unsubstituted silyl group, a halogen atom, a deuteriumatom, or a hydrogen atom.

L₁ and L₂ may each independently be selected from or include, e.g., adirect linkage (e.g., single bond), a substituted or unsubstituted alkylgroup having 6 to 30 carbon atoms, a substituted or unsubstitutedarylene group having 6 to 30 ring carbon atoms, or a substituted orunsubstituted heteroarylene group having 5 to 30 ring carbon atoms.

a, b, and c may each independently be, e.g., an integer of 0 to 4, d maybe, eg., an integer of 0 to 3, and e may be, e.g., an integer of 0 to 5,

in the case where e is 2 or more (e.g., an integer of 2 to 5), adjacentgroups or ones of of R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, R₉, R₁₀, R₁₁, R₁₂,R₁₃, R₁₄ and R₁₅ may be separate or may be bound to form a ring fromeach other.

In Formula 1, Ar₁ and Ar₂ may each independently be selected from orinclude, e.g., a substituted or unsubstituted aryl group having 6 to 30ring carbon atoms, a substituted or unsubstituted heteroaryl grouphaving 5 to 30 ring carbon atoms, a substituted or unsubstituted alkylgroup having 1 to 20 carbon atoms, a substituted or unsubstituted silylgroup, a halogen atom, a deuterium atom, or a hydrogen atom.

In an implementation, Ar₁ and Ar₂ may each independently be selectedfrom or include, e.g., a substituted or unsubstituted phenyl group, asubstituted or unsubstituted biphenyl group, a substituted orunsubstituted naphthyl group, a substituted or unsubstituted fluorenylgroup, or a substituted or unsubstituted acridine group.

In an implementation, Ar₁ and Ar₂ may each independently be selectedfrom or include, e.g., an unsubstituted or alkyl substituted fluorenylgroup, an unsubstituted or alkyl substituted acridine group, anunsubstituted or alkyl substituted phenyl group, an unsubstituted oralkoxy substituted phenyl group, an unsubstituted or halogen substitutedphenyl group, an unsubstituted or nitrile substituted phenyl group, oran unsubstituted or aryl substituted phenyl group.

In an implementation, Ar₁ and Ar₂ may each independently be selectedfrom or include, e.g., an unsubstituted or phenyl substituted phenylgroup or an unsubstituted or naphthyl substituted phenyl group.

In an implementation, L₁ in Formula 1 may be selected from or include,e.g., a direct linkage, a substituted or unsubstituted alkyl grouphaving 6 to 30 carbon atoms, a substituted or unsubstituted arylenegroup having 6 to 30 ring carbon atoms, or a substituted orunsubstituted heteroarylene group having 5 to 30 ring carbon atoms.

In an implementation, L₁ in Formula 1 may be selected from or include,e.g., a substituted or unsubstituted phenylene group, a substituted orunsubstituted divalent biphenyl, or a substituted or unsubstitutedfluorenylene group.

In an implementation, in Formula 1, R₁ and R₂ may each independently beselected from or include, e.g., a substituted or unsubstituted arylgroup having 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring carbon atoms, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted silyl group, a halogen atom, a deuterium atom, or ahydrogen atom.

In Formula 1, a and b may each independently be, e.g., an integer of 0to 4.

In the case where a is an integer of 1 or more (e.g., 1 to 4), aplurality of R₁ may be the same or different, or at least one R₁ may bedifferent. In the case where b is an integer of 1 or more (e.g., 1 to4), a plurality of R₂ may be the same or different, or at least one R₂may be different.

In an implementation, the first hole transport material may include,e.g., one of the following Compounds 1-1 to 1-20.

In an implementation, in Formula 2, Ar₃ and Ar₄ may each independentlybe selected from or include, e.g., a substituted or unsubstituted arylgroup having 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring carbon atoms, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted silyl group, a halogen atom, a deuterium atom, or ahydrogen atom.

In an implementation, in Formula 2, Ar₃ and Ar₄ may each independentlybe selected from or include, e.g., a substituted or unsubstituted phenylgroup, a substituted or unsubstituted biphenyl group, a substituted orunsubstituted naphthyl group, a substituted or unsubstituted fluorenylgroup, or a substituted or unsubstituted spirobifluorenyl group.

In an implementation, in Formula 2, Ar₃ and Ar₄ may each independentlybe selected from or include, e.g., an unsubstituted or alkyl substitutedfluorenyl group, an unsubstituted or alkyl substituted acridine group,an unsubstituted or alkyl substituted phenyl group, an unsubstituted oralkoxy substituted phenyl group, an unsubstituted or halogen substitutedphenyl group, an unsubstituted or nitrile substituted phenyl group, oran unsubstituted or aryl substituted phenyl group.

In an implementation, in Formula 2, Ar₃ and Ar₄ may each independentlybe selected from or include, e.g., an unsubstituted or phenylsubstituted phenyl group or an unsubstituted or naphthyl substitutedphenyl group.

In an implementation, in Formula 2, Ar₃ and Ar₄ may combine with eachother to form a ring. In an implementation, in Formula 2, Ar₃ and Ar₄may combine with each other to form a substituted or unsubstituted arylgroup. In an implementation, in Formula 2, Ar₃ and Ar₄ may combine witheach other to form a substituted or unsubstituted acridine group.

In an implementation, in Formula 2, Ar₅ may be selected from or include,e.g., a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring carbon atoms, a substituted or unsubstituted alkyl grouphaving 1 to 20 carbon atoms, a substituted or unsubstituted silyl group,a halogen atom, a deuterium atom, or a hydrogen atom.

In an implementation, Ar₅ may be selected from or include, e.g., asubstituted or unsubstituted phenyl group, a substituted orunsubstituted dibenzofuran group, or a substituted or unsubstitutedpyridine group.

In an implementation, in Formula 2, L₂ may be selected from or include,e.g., a direct linkage, a substituted or unsubstituted alkyl grouphaving 6 to 30 carbon atoms, a substituted or unsubstituted arylenegroup having 6 to 30 ring carbon atoms, or a substituted orunsubstituted heteroarylene group having 5 to 30 ring carbon atoms.

In an implementation, L₂ may be selected from or include, e.g., asubstituted or unsubstituted phenylene group, a substituted orunsubstituted divalent biphenyl group, or a substituted or unsubstitutedfluorenylene group.

In an implementation, in Formula 2, R₃ and R₄ may each independently beselected from or include, e.g., a substituted or unsubstituted arylgroup having 6 to 30 ring carbon atoms, substituted or unsubstitutedheteroaryl group having 5 to 30 ring carbon atoms, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted silyl group, a halogen atom, a deuterium atom, or ahydrogen atom.

In an implementation, in Formula 2, c may be, e.g., an integer of 0 to4. In an implementation, in Formula 2, d may be, e.g., an integer of 0to 3.

In the case where c is an integer of 1 or more (e.g., 1 to 4), aplurality of R₃ may be the same or different, or at least one R₃ may bedifferent. In the case where d is an integer of 1 or more (e.g., 1 to3), a plurality of R₄ may be the same or different, or at least one R₄may be different.

In an implementation, the second hole transport material may include oneof the following Compounds 2-1 to 2-20.

In an implementation, in Formula 3, Ar₆ and Ar₇ may each independentlybe selected from or include, e.g., a substituted or unsubstituted arylgroup having 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring carbon atoms, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted silyl group, a halogen atom, a deuterium atom, or ahydrogen atom.

In an implementation, Ar₆ and Ar₇ may each independently be selectedfrom or include, e.g., a substituted or unsubstituted phenyl group, asubstituted or unsubstituted biphenyl group, a substituted orunsubstituted naphthyl group, a substituted or unsubstituteddibenzofuran group, or a substituted or unsubstituted dibenzothiophenegroup.

In an implementation, Ar₆ and Ar₇ may each independently be selectedfrom or include, e.g., an unsubstituted or aryl substituted phenylgroup, an unsubstituted or silyl substituted phenyl group, anunsubstituted or aryl substituted dibenzothiophene group, or anunsubstituted or aryl substituted biphenyl group.

In an implementation, Ar₆ and Ar₇ may each independently be selectedfrom or include, e.g., an unsubstituted or phenyl substituted phenylgroup, an unsubstituted or naphthyl substituted phenyl group, anunsubstituted or benzo[def]carbazole substituted phenyl group, anunsubstituted or triphenylsilyl substituted phenyl group.

In an implementation, Ar₆ and Ar₇ may each independently be selectedfrom or include, e.g., an unsubstituted or dibenzofuran substitutedbiphenyl group, an unsubstituted or benzo[def]carbazole substitutedbiphenyl group, or an unsubstituted or carbazole substituted biphenylgroup.

In an implementation, in Formula 3, R₅ may be selected from or include,e.g., a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring carbon atoms, a substituted or unsubstituted alkyl grouphaving 1 to 20 carbon atoms, a substituted or unsubstituted silyl group,a halogen atom, a deuterium atom, or a hydrogen atom.

In an implementation, in Formula 3, R₅ may be selected from or include,e.g., a substituted or unsubstituted phenyl group, a substituted orunsubstituted biphenyl group, a substituted or unsubstituted naphthylgroup, a substituted or unsubstituted fluorenyl group, a substituted orunsubstituted dibenzofuran group, or a substituted or unsubstitutedbenzo[def]carbazole group.

In an implementation, in Formula 3, R₅ may be selected from or include,e.g., an unsubstituted or silyl substituted phenyl group, anunsubstituted or aryl substituted fluorenyl group, an unsubstituted oraryl substituted phenyl group, an unsubstituted or aryl substitutedbenzo[def]carbazole group, or an unsubstituted or aryl substituteddibenzofuran group.

In an implementation, in Formula 3, R₅ may be selected from or include,e.g., an unsubstituted or naphthyl substituted phenyl group, anunsubstituted or carbazole substituted phenyl group, an unsubstituted orbenzo[def]carbazole substituted phenyl group, an unsubstituted ordibenzofuran substituted phenyl group, or an unsubstituted ordibenzofuran substituted biphenyl group.

In Formula 3, e may be, e.g., an integer of 0 to 5. In the case where eis an integer of 1 or more (e.g., 1 to 5), a plurality of R5 may be thesame or different, or at least one R₅ may be different.

In an implementation, the third hole transport material may include oneof the following Compounds 3-1 to 3-20.

In an implementation, in Formula 4, Ar₈ may be selected from or include,e.g., a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring carbon atoms, a substituted or unsubstituted alkyl grouphaving 1 to 20 carbon atoms, a substituted or unsubstituted silyl group,a halogen atom, a deuterium atom, or a hydrogen atom.

In an implementation, in Formula 4, Ar₈ may be selected from or include,e.g., a substituted or unsubstituted phenyl group, a substituted orunsubstituted biphenyl group, or a substituted or unsubstitutedcarbazole group.

In an implementation, in Formula 4, Ar₈ may be selected from or include,e.g., an unsubstituted or silyl substituted phenyl group, anunsubstituted or aryl substituted phenyl group, an unsubstituted or arylsubstituted biphenyl group, or an unsubstituted or aryl substitutedcarbazole group.

In an implementation, in Formula 4, Ar₈ may be selected from or include,e.g., an unsubstituted or triphenylsilyl substituted phenyl group, anunsubstituted or phenanthryl substituted phenyl group, an unsubstitutedor dibenzofuran substituted phenyl group, an unsubstituted or carbazolesubstituted phenyl group, an unsubstituted or triphenylene substitutedphenyl group, or an unsubstituted or phenyl substituted carbazole group.

In an implementation, in Formula 4, Ar₈ may combine with at least one ofR₆ or R₁₃ to form a ring. Ar₈ may combine with at least one of R₆ or R₁₃and thus, the fourth hole transport material may include substituted orunsubstituted benzo furo quinolino acridine in the chemical structurethereof.

In an implementation, in Formula 4, R₉ and R₁₀ may combine with eachother to form a ring that includes X. X may be a direct linkage orCR₁₄R₁₅. N and X combining with Ar₈ may form a pentagonal ring or ahexagonal ring.

In an implementation, in Formula 4, R₉ and R₁₀ may combine or bond witheach other to form a ring, and thus, the fourth hole transport materialmay include, e.g., a substituted or unsubstituted indolocarbazole group,a substituted or unsubstituted benzo[def]carbazole group, a substitutedor unsubstituted benzocarbazole group, a substituted or unsubstitutedbenzofurocarbazole group, or a substituted or unsubstitutedbenzo[def]indolocarbazole group in the compound structure thereof.

In an implementation, in Formula 4, R₆, R₇, R₈, R₉, R₁₀, R₁₁, R₁₂, R₁₃,R₁₄ and R₁₅ may each independently be selected from or include, e.g., asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring carbon atoms, a substituted or unsubstituted alkyl group having 1to 20 carbon atoms, a substituted or unsubstituted silyl group, ahalogen atom, a deuterium atom, or a hydrogen atom.

In an implementation, in Formula 4, R₆, R₇, R₈, R₉, R₁₀, R₁₁, R₁₂, R₁₃,R₁₄ and R₁₅ may each independently be selected from or include, e.g., asubstituted or unsubstituted phenyl group, a substituted orunsubstituted naphthyl group, a substituted or unsubstituted carbazolegroup, a substituted or unsubstituted benzo[def]carbazole group, asubstituted or unsubstituted fluorenyl group, a substituted orunsubstituted dibenzofuran group, a substituted or unsubstitutedtriphenylene group, a substituted or unsubstituted phenanthrene group,or a substituted or unsubstituted dibenzosilole group.

In an implementation, in Formula 4, R₆, R₇, R₈, R₉, R₁₀, R₁₁, R₁₂, R₁₃,R₁₄ and R₁₅ may each independently be selected from or include, e.g., anunsubstituted or aryl substituted phenyl group, an unsubstituted orsilyl substituted phenyl group, an unsubstituted or aryl substitutednaphthyl group, an unsubstituted or aryl substituted carbazole group, anunsubstituted or aryl substituted benzo[def]carbazole group, anunsubstituted or aryl substituted fluorenyl group, an unsubstituted oraryl substituted dibenzofuran group, an unsubstituted or arylsubstituted triphenylene group, an unsubstituted or aryl substitutedphenanthrene group, or an unsubstituted or aryl substituteddibenzosilole group.

In an implementation, in Formula 4, R₆, R₇, R₈, R₉, R₁₀, R₁₁, R₁₂, R₁₃,R₁₄ and R₁₅ may each independently be selected from or include, e.g., anunsubstituted or triphenylsilyl substituted phenyl group, anunsubstituted or carbazole substituted phenyl group, an unsubstituted ordibenzofuran substituted phenyl, an unsubstituted or carbazolesubstituted naphthyl group, an unsubstituted or phenyl substitutedcarbazole group, an unsubstituted or carbazole substituted carbazolegroup, an unsubstituted or phenyl substituted benzo[def]carbazole group,an unsubstituted or carbazole substituted benzo[def]carbazole group, anunsubstituted or carbazole substituted fluorenyl group, an unsubstitutedor carbazole substituted dibenzofuran group, an unsubstituted orbenzo[def]carbazole substituted dibenzofuran group, an unsubstituted orcarbazole substituted triphenylene group, an unsubstituted or carbazolesubstituted phenanthrene group, or an unsubstituted or carbazolesubstituted dibenzosilole group.

In an implementation, the fourth hole transport material may include,e.g., one of the following Compounds 4-1 to 4-20.

In an implementation, the hole transport region HTR may further includea charge generating material in addition to the above-describedmaterials to help improve conductivity. The charge generating materialmay be dispersed in the hole transport region HTR uniformly ornon-uniformly. The charge generating material may be, e.g., a p-dopant.In an implementation, the p-dopant may be one of a quinone derivative, ametal oxide, or a cyano group-containing compound. Examples of thep-dopant may include a quinone derivative such astetracyanoquinodimethane (TCNQ), and2,3,5,6-tetrafluoro-tetracyanoquinodimethane (F4-TCNQ), a metal oxidesuch as tungsten oxide, and molybdenum oxide.

As described above, the hole transport region HTR may further include atleast one of a hole buffer layer or an electron blocking layer inaddition to the hole injection layer HIL, the first hole transport layerHTL1 and the second hole transport layer HTL2. The hole buffer layer mayhelp compensate an optical resonance distance according to thewavelength of light emitted from the emission layer EML and increaselight emission efficiency. Materials included in the hole transportregion HTR may be used as materials included in the hole buffer layer.The electron blocking layer is a layer that helps to prevent electroninjection from the electron transport region ETR into the hole transportregion HTR.

The emission layer EML may be provided on the hole transport region HTR.The emission layer EML may be provided on the second hole transportlayer HTL2. In an implementation, the thickness of the emission layerEML may be, e.g., from about 100 Å to about 300 Å. In an implementation,the emission layer EML may have a single layer formed using a singlematerial, a single layer formed using a plurality of differentmaterials, or a multilayer structure having a plurality of layers formedusing a plurality of different materials.

The emission layer EML may emit one of red light, green light, bluelight, white light, yellow light, or cyan light. The emission layer EMLmay include a fluorescent material or a phosphorescent material. Theemission layer EML may include a thermally activated delayedfluorescence material. In an implementation, the emission layer EML mayinclude a host and a dopant. The emission layer EML may have a thicknessof about 10 nm to about 60 nm.

In an implementation, the host may include, e.g.,tris(8-hydroxyquinolino)aluminum (Alq3),4,4’-bis(N-carbazolyl)-1,1′-biphenyl (CBP), poly(n-vinylcarbazole)(PVK), 9,10-di(naphthaline-2-yl)anthracene (ADN),4,4′,4″-tris(carbazol-9-yl)-triphenylamine (TCTA),1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene (TPBi),3-tert-butyl-9,10-di(naphth-2-yl)anthracene (TBADN), distyrylarylene(DSA), 4,4′-bis(9-carbazolyl)-2,2′-dimethyl-biphenyl (CDBP),2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), etc.

In an implementation, the dopant may include an emission material(thermally activated delayed fluorescence material) containing a donorand an acceptor.

When the emission layer EML emits red light, the emission layer EML mayinclude as a host material, e.g., 4,4′-bis(9-carbazolyl)-1,1′-biphenyl(CBP), and 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene (BmPyPb). The dopantmay be selected from, for example,4,4′,4″-(1,3,3a¹,4,6,7,9-heptaazaphenalene-2,5,8-triyl)tris(N,N-bis(4-(tert-butyl)phenyl)aniline)(HAP-3TPA). 2,4,6-tri(4-(10H-phenoxazin-10H-yl)phenyl)-1,3,5-triazine(tri-PXZ-TRZ), or derivatives thereof.

When the emission layer EML emits green light, the emission layer EMLmay include as a host material, e.g., N,N′-dicarbazolyl-3,5-benzene(mCP), and 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene (BmPyPb). The dopantmay be selected from, for example,1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN),2,5-bis(carbazol-9-yl)-1,4-dicyanobenzene (CzTPN), or derivativesthereof.

When the emission layer EML emits blue light, the emission layer EML mayinclude as a host material, e.g.,4,4′,4″-tris(carbazol-9-yl)-triphenylamine (TCTA). The dopant may beselected from, for example,bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (DMAC-DSP),4,5-bis(carbazol-9-yl)-1,2-dicyanobenzene (2CzPN), m-bisCzTRZ, orderivatives thereof.

The electron transport region ETR may be provided on the emission layerEML.

In an implementation, the electron transport region ETR may include,e.g., at least one of an electron blocking layer, an electron transportlayer ETL or an electron injection layer EIL.

In an implementation, the electron transport region ETR may have asingle layer formed using a single material, a single layer formed usinga plurality of different materials, or a multilayer structure having aplurality of layers formed using a plurality of different materials.

For example, the electron transport region ETR may have a single layerstructure of the electron injection layer EIL or the electron transportlayer ETL, or a single layer structure formed using an electroninjection material and an electron transport material. In animplementation, the electron transport region ETR may have a singlelayer structure having a plurality of different materials, or astructure laminated from the anode AN of electron transport layerETL/electron injection layer EIL, or hole blocking layer/electrontransport layer ETL/electron injection layer EIL. In an implementation,the thickness of the electron transport region ETR may be, e.g., fromabout 1,000 Å to about 1,500 Å.

The electron transport region ETR may be formed using various methodssuch as a vacuum deposition method, a spin coating method, a castmethod, a Langmuir-Blodgett (LB) method, an inkjet printing method, alaser printing method, and a laser induced thermal imaging (LITI)method.

In the case where the electron transport region ETR includes theelectron transport layer ETL, the electron transport region ETR mayinclude, e.g., tris(8-hydroxyquinolinato)aluminum (Alq3),1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene,2,4,6-tris(3′-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine,2-(4-(N-phenylbenzoimidazolyl-1-ylphenyl)-9,10-dinaphthylanthracene,1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl (TPBi),2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP),4,7-diphenyl-1,10-phenanthroline (Bphen),3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ),4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ),2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD),bis(2-methyl-8-quinolinolato-N1,O8)-(1,1′-biphenyl-4-olato)aluminum(BAlq), berylliumbis(benzoquinolin-10-olate (Bebq2),9,10-di(naphthalene-2-yl)anthracene (ADN), or a mixture thereof. In animplementation, the thickness of the electron transport layer ETL may befrom about 100 Å to about 1,000 Å, e.g., about 150 Å to about 500 Å. Ifthe thickness of the electron transport layer ETL satisfies theabove-described range, satisfactory electron transport property may beobtained without substantial increase of a driving voltage.

When the electron transport region ETR includes the electron injectionlayer EIL, the electron transport region ETR may include, e.g., LiF,lithium quinolone (LiQ), Li₂O, BaO, NaCl, CsF, a metal in lanthanoidessuch as Yb, or a metal halide such as RbCl and RbI. In animplementation, the electron injection layer EIL also may be formedusing a mixture material of an electron transport material and aninsulating organo metal salt. The organo metal salt may be a materialhaving an energy band gap of about 4 eV or more. In an implementation,the organo metal salt may include, e.g., a metal acetate, a metalbenzoate, a metal acetoacetate, a metal acetylacetonate, or a metalstearate. In an implementation, the thickness of the electron injectionlayer EIL may be from about 1 Å to about 100 Å, or from about 3 Å toabout 90 Å. In the case where the thickness of the electron injectionlayer EIL satisfies the above described range, satisfactory electroninjection property may be obtained without inducing the substantialincrease of a driving voltage.

The electron transport region ETR may include a hole blocking layer asdescribed above. In an implementation, the hole blocking layer mayinclude, e.g., at least one of2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), or4,7-diphenyl-1,10-phenanthroline (Bphen).

The cathode CAT may be provided on the electron transport region ETR.The cathode CAT may be a common electrode or a negative electrode. Thecathode CAT may be a transmissive electrode, a transflective electrode,or a reflective electrode. In the case where the cathode CAT is thetransmissive electrode, the cathode CAT may include a transparent metaloxide, e.g., ITO, IZO, ZnO, ITZO, etc.

In the case where the cathode CAT is the transflective electrode or thereflective electrode, the cathode CAT may include, e.g., Ag, Mg, Cu, Al,Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Ca, LiF/Al, Mo, Ti, a compoundthereof, or a mixture thereof (for example, a mixture of Ag and Mg). Inan implementation, the cathode CAT may have a multilayered structureincluding a reflective layer or a transflective layer formed using theabove-described materials and a transparent conductive layer formedusing ITO, IZO, ZnO, ITZO, etc.

In an implementation, the cathode CAT may be connected with an auxiliaryelectrode. In the case where the cathode CAT is connected with theauxiliary electrode, the resistance of the cathode CAT may decrease.

In the organic light emitting device 10, according to the application ofa voltage to each of the anode AN and the cathode CAT, holes injectedfrom the anode AN may move via the hole transport region HTR to theemission layer EML, and electrons injected from the cathode CAT may movevia the electron transport region ETR to the emission layer EML. Theelectrons and the holes may be recombined in the emission layer EML togenerate excitons, and the excitons may emit light via transition froman excited state to a ground state.

In the case where the organic light emitting device 10 is a top emissiontype, the anode AN may be a reflective electrode, and the cathode CATmay be a transmissive electrode or a transflective electrode. In thecase where the organic light emitting device 10 is a bottom emissiontype, the anode AN may be a transmissive electrode or a transflectiveelectrode, and the cathode CAT may be a reflective electrode.

The organic light emitting device according to an embodiment of thepresent disclosure may include, e.g., a first hole transport layerincluding a first hole transport material or a second hole transportmaterial (each containing an amine) and a second hole transport layerincluding a third hole transport material (containing one amine group)or a fourth hole transport material (containing a ring that includes N).Each of the first hole transport material and the second hole transportmaterial may include the amine, and hole transport properties may behigh. The third hole transport material may include the one amine groupand the fourth hole transport material may include the N-containingring, charge tolerance may be high. Accordingly, a charge balance ofholes and electrons in an emission layer may be appropriate in theorganic light emitting device according to an embodiment of the presentdisclosure, and high emission efficiency and long life may beaccomplished.

The following Examples and Comparative Examples are provided in order tohighlight characteristics of one or more embodiments, but it will beunderstood that the Examples and Comparative Examples are not to beconstrued as limiting the scope of the embodiments, nor are theComparative Examples to be construed as being outside the scope of theembodiments. Further, it will be understood that the embodiments are notlimited to the particular details described in the Examples andComparative Examples.

Examples Synthetic Examples

[Synthesis of Compounds]

(Synthesis of Compound A)

Under an Ar atmosphere, 2.87 g of 9-phenylcarbazole-3-boronic acid, 2.99g of 1-bromo-4-iodobenzene, 0.33 g of Pd(PPh₃)₄, and 1.86 g of potassiumcarbonate were added to a 200 mL, three-necked flask and were heated andstirred in a mixed solvent of 50 mL of toluene and 20 mL of water atabout 90° C. for about 8 hours. After cooling in the air, water wasadded, an organic layer was separated, and solvents were distilled. Thecrude product thus obtained was separated by silica gel columnchromatography (using a mixed solvent of dichloromethane and hexane) andrecrystallized using a mixed solvent of toluene and hexane to obtain3.50 g (yield 88%) of Compound A as a white solid. The molecular weightof Compound A as measured by FAB-MS was 398. FAB-MS was measured usingJMS-700V manufactured by JEOL Co., and ¹H-NMR was measured usingAVAVCE300M manufactured by Bruker Biospin KK Co.

(Synthesis of Compound 2-3)

Under an Ar atmosphere, 3.98 g of Compound A, 3.62 g ofN-[1,1′-biphenyl]-4-yl-9,9-dimethyl-9H-fluoren-2-amine, 0.563 g ofPd(dba)₂, 0.19 g of (t-Bu)₃P, and 6.44 g of sodium t-butoxide were addedto a 200 mL, three-necked flask and were heated and refluxed in 130 mLof a toluene solvent for about 8 hours. After cooling in the air, waterwas added, an organic layer was separated, and solvents were distilled.The crude product thus obtained was separated by silica gel columnchromatography (using a mixed solvent of toluene and hexane) andrecrystallized using a mixed solvent of toluene and hexane to obtain4.75 g (yield 70%) of Compound 2-3 as a yellow solid. The molecularweight of Compound 2-3 measured by FAB-MS was 679. FAB-MS was measuredusing JMS-700V manufactured by JEOL Co., and ¹H-NMR was measured usingAVAVCE300M manufactured by Bruker Biospin KK Co.

(Synthesis of Compound 2-11)

Compound 2-11 was synthesized by performing the same synthetic methoddescribed in Synthesis of Compound 2-3 except for usingN-(9,9-dimethyl-9H-fluoren-2-yl)-9,9-dimethyl-9H-fluoren-2-amine insteadof N-[1,1′-biphenyl]-4-yl-9,9-dimethyl-9H-fluoren-2-amine. The molecularweight of Compound 2-11 measured by FAB-MS was 719. FAB-MS was measuredusing JMS-700V manufactured by JEOL Co., and ¹H-NMR was measured usingAVAVCE300M manufactured by Bruker Biospin KK Co.

(Synthesis of Compound 2-19)

Compound 2-19 was synthesized by performing the same synthetic methoddescribed in Synthesis of Compound 2-3 except for usingN-[4-(1-naphthalenyephenyl]-[1,1′-biphenyl]-4-amine instead ofN-[1,1′-biphenyl]-4-yl-9,9-dimethyl-9H-fluoren-2-amine. The molecularweight of Compound 2-19 measured by FAB-MS was 689. FAB-MS was measuredusing JMS-700V manufactured by JEOL Co., and ¹H-NMR was measured usingAVAVCE300M manufactured by Bruker Biospin KK Co.

(Synthesis of Compound 3-2)

Under an Ar atmosphere, 4.40 g of (4-(bis(1,1’-biphenyl)-4-yl)amino)phenylboronic acid, 4.15 g of 4-bromotetraphenylsilane, 2.263 g ofPd(PPh₃)₄, and 2.44 g of potassium carbonate were added to a 200 mL,three-necked flask and were heated and stirred in a mixed solvent of 50mL of toluene and 20 mL of water at about 90° C. for about 8 hours.After cooling in the air, water was added, an organic layer wasseparated, and solvents were distilled. The crude product thus obtainedwas separated by silica gel column chromatography (using a mixed solventof dichloromethane and hexane) and recrystallized using a mixed solventof toluene and hexane to obtain 6.33 g (yield 88%) of Compound 3-2 as awhite solid. The molecular weight of Compound 3-2 measured by FAB-MS was719. FAB-MS was measured using JMS-700V manufactured by JEOL Co., and¹H-NMR was measured using AVAVCE300M manufactured by Bruker Biospin KKCo.

(Synthesis of Compound 3-17)

Compound 3-17 was synthesized by performing the same synthetic methoddescribed in Synthesis of Compound 3-2 except for using9-(3-bromophenyl)-9H-carbazole instead of 4-bromotetraphenylsilane. Themolecular weight of Compound 3-17 measured by FAB-MS was 639. FAB-MS wasmeasured using JMS-700V manufactured by JEOL Co., and ¹H-NMR wasmeasured using AVAVCE300M manufactured by Bruker Biospin KK Co.

[Manufacture of Organic Light Emitting Device]

An anode was formed using ITO to a thickness of about 150 nm, a holeinjection layer was formed using2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN) to athickness of about 5 nm, a first hole transport layer was formed using amaterial shown in the following Table 1 to a thickness of about 10 nm, asecond hole transport layer was formed using a material shown in thefollowing Table 1 to a thickness of about 100 nm, an emission layer wasformed using 2,4,5,6-tetrakis(carbazol-9-yl)-1,3-dicyanobenzene (4CzIPN)and 3,3-di(9H-carbazol-9-yl)biphenyl (mCBP) to a thickness of about 20nm, a first electron transport layer was formed using2,4,6-tris(biphenyl-3-yl)-1,3,5-triaxine (T2T) to a thickness of about 5nm, a second electron transport layer was formed using BPy-TP2 to athickness of about 25 nm, an electron injection layer was formed usingLiF to a thickness of about 1 nm, and a cathode was formed using Al to athickness of about 100 nm.

The current density of a device was measured using Source Meter of 2400Series manufactured by Keithley Instruments Co., a voltage was measuredusing CS-200 Chroma Meter manufactured by Konica Minolta Holdings Co.,and emission efficiency was measured using PC Program LabVIEW8.2 formeasurement, manufactured by National Instruments Co., Ltd. in Japan.

TABLE 1 Device First hole Second hole Emission manufacturing transporttransport efficiency Life (h) example layer layer (cd/A) (LT90) Example1 1-1  3-2  41 150 Example 2 1-3  3-8  40 145 Example 3 1-10 3-10 42 149Example 4 2-3  3-15 41 160 Example 5 2-11 3-16 40 162 Example 6 2-193-17 41 164 Example 7 1-17 3-5  42 153 Example 8 1-18 3-6  41 155Example 9 2-7  3-5  40 156 Example 10 2-19 3-6  40 154 Example 11 1-1 4-2  41 150 Example 12 1-3  4-8  41 151 Example 13 1-10 4-10 42 153Example 14 2-3  4-15 41 161 Example 15 2-11 4-16 42 158 Example 16 2-194-17 41 162 Comparative Tris-PCz  — 28 80 Example 1 Comparative 2-3 Comparative 29 95 Example 2 Compound 1

Tris-PCz:9,9’-diphenyl-6-(9-phenyl-9H-carbazol-3-yl)-9H,9′H-3,3′-bicarbazole

Comparative Compound 1

Referring to Table 1, the organic light emitting devices of Examples 1to 16 had higher emission efficiency and longer life than the organiclight emission devices of Comparative Examples 1 and 2. In ComparativeExample 1, Tris-PCz (not including amine) was included as the materialof a first hole transport layer but was not included in a second holetransport layer. Accordingly, a hole transport property was low, chargebalance was low, and device life was short. In addition, in ComparativeExample 2, Comparative Compound 1 (which is a diamine compound) wasincluded in a second hole transport layer, and charge tolerance was low,and thus, device life was short.

By way of summation and review, in the application of an organic lightemitting device to a display device, a decrease of the driving voltage,an increase of emission efficiency, and an increase of life of theorganic light emitting device may be desirable.

The organic light emitting device according to an embodiment of thepresent disclosure may accomplish high emission efficiency and longlife.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. An organic light emitting device, comprising: ananode; a hole transport region on the anode; an emission layer on thehole transport region; an electron transport region on the emissionlayer; and a cathode on the electron transport region, wherein the holetransport region includes: a first hole transport layer including afirst hole transport material represented by the following Formula 1 ora second hole transport material represented by the following Formula 2;and a second hole transport layer on the first hole transport layer, thesecond hole transport layer including a third hole transport materialrepresented by the following Formula 3 or a fourth hole transportmaterial represented by the following Formula 4:

wherein, in Formulae 1, 2, 3 and 4, Ar₁, Ar₂, Ar₃, Ar₄, Ar₅, Ar₆, Ar₇,and Ar₈ are each independently a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring carbon atoms, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted silyl group, a halogen atom, a deuterium atom, or ahydrogen atom, X is a direct linkage or CR₁₄R₁₅, R₁, R₂, R₃, R₄, R₅, R₆,R₇, R₈, R₉, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄ and R₁₅ are each independently asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring carbon atoms, a substituted or unsubstituted alkyl group having 1to 20 carbon atoms, a substituted or unsubstituted silyl group, ahalogen atom, a deuterium atom, or a hydrogen atom, L₁ and L₂ are eachindependently a direct linkage, a substituted or unsubstituted alkylgroup having 6 to 30 carbon atoms, a substituted or unsubstitutedarylene group having 6 to 30 ring carbon atoms, or a substituted orunsubstituted heteroarylene group having 5 to 30 ring carbon atoms, a,b, and c are each independently an integer of 0 to 4, d is an integer of0 to 3, and e is an integer of 0 to 5, in the case where e is an integerof 2 to 5, adjacent ones of R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, R₉, R₁₀,R₁₁, R₁₂, R₁₃, R₁₄ and R₁₅ are separate or are bound form a ring.
 2. Theorganic light emitting device as claimed in claim 1, wherein theemission layer includes an emission material containing a donor and anacceptor, the emission material being a thermally activated delayedfluorescence material.
 3. The organic light emitting device as claimedin claim 1, wherein: the first hole transport layer includes the firsthole transport material represented by Formula 1, and Ar₁ and Ar₂ inFormula 1 are each independently a substituted or unsubstituted phenylgroup, a substituted or unsubstituted biphenyl group, a substituted orunsubstituted naphthyl group, a substituted or unsubstituted fluorenylgroup, or a substituted or unsubstituted acridine group.
 4. The organiclight emitting device as claimed in claim 1, wherein: the first holetransport layer includes the first hole transport material representedby Formula 1, and L₁ in Formula 1 is a substituted or unsubstitutedphenylene group, a substituted or unsubstituted divalent biphenyl group,or a substituted or unsubstituted fluorenylene group.
 5. The organiclight emitting device as claimed in claim 1, wherein: the first holetransport layer includes the first hole transport material representedby Formula 1, and the first hole transport material includes one of thefollowing Compounds 1-1 to 1-20:


6. The organic light emitting device as claimed in claim 1, wherein: thefirst hole transport layer includes the second hole transport materialrepresented by Formula 2, and Ar₃ and Ar₄ in Formula 2 are bound to forma ring.
 7. The organic light emitting device as claimed in claim 1,wherein: the first hole transport layer includes the second holetransport material represented by Formula 2, and Ar₃ and Ar₄ in Formula2 are each independently a substituted or unsubstituted phenyl group, asubstituted or unsubstituted biphenyl group, a substituted orunsubstituted naphthyl group, a substituted or unsubstituted fluorenylgroup, or a substituted or unsubstituted spirobifluorenyl group.
 8. Theorganic light emitting device as claimed in claim 1, wherein: the firsthole transport layer includes the second hole transport materialrepresented by Formula 2, and Ar₅ in Formula 2 is a substituted orunsubstituted phenyl group, a substituted or unsubstituted dibenzofurangroup, or a substituted or unsubstituted pyridine group.
 9. The organiclight emitting device as claimed in claim 1, wherein: the first holetransport layer includes the second hole transport material representedby Formula 2, and L₂ in Formula 2 is a direct linkage, a substituted orunsubstituted phenylene group, a substituted or unsubstituted divalentbiphenyl group, or a substituted or unsubstituted fluorenylene group.10. The organic light emitting device as claimed in claim 1, wherein:the first hole transport layer includes the second hole transportmaterial represented by Formula 2, and the second hole transportmaterial includes one of the following Compounds 2-1 to 2-20:


11. The organic light emitting device as claimed in claim 1, wherein:the second hole transport layer includes the third hole transportmaterial represented by Formula 3, and Ar₆ and Ar₇ in Formula 3 are eachindependently a substituted or unsubstituted phenyl group, a substitutedor unsubstituted biphenyl group, a substituted or unsubstituted naphthylgroup, a substituted or unsubstituted dibenzofuran group, or asubstituted or unsubstituted dibenzothiophene group.
 12. The organiclight emitting device as claimed in claim 1, wherein: the second holetransport layer includes the third hole transport material representedby Formula 3, and R₅ in Formula 3 is a substituted or unsubstitutedphenyl group, a substituted or unsubstituted biphenyl group, asubstituted or unsubstituted naphthyl group, a substituted orunsubstituted fluorenyl group, a substituted or unsubstituteddibenzofuran group, or a substituted or unsubstitutedbenzo[def]carbazole group.
 13. The organic light emitting device asclaimed in claim 1, wherein: the second hole transport layer includesthe third hole transport material represented by Formula 3, and thethird hole transport material includes one of the following Compounds3-1 to 3-20:


14. The organic light emitting device as claimed in claim 1, wherein:the second hole transport layer includes the fourth hole transportmaterial represented by Formula 4, and Ar₈ in Formula 4 combines with atleast one of R₆ or R₁₃ to form a ring.
 15. The organic light emittingdevice as claimed in claim 1, wherein: the second hole transport layerincludes the fourth hole transport material represented by Formula 4,and R₉ and R₁₀ in Formula 4 combine to form a ring that includes X. 16.The organic light emitting device as claimed in claim 1, wherein: thesecond hole transport layer includes the fourth hole transport materialrepresented by Formula 4, and Ar₅ in Formula 4 is a substituted orunsubstituted phenyl group, a substituted or unsubstituted biphenylgroup, or a substituted or unsubstituted carbazole group.
 17. Theorganic light emitting device as claimed in claim 1, wherein: the secondhole transport layer includes the fourth hole transport materialrepresented by Formula 4, and R₆, R₇, R₈, R₉, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄and R₁₅ in Formula 4 are each independently a substituted orunsubstituted phenyl group, a substituted or unsubstituted naphthylgroup, substituted or unsubstituted carbazole group, a substituted orunsubstituted benzo[def]carbazole group, a substituted or unsubstitutedfluorenyl group, a substituted or unsubstituted dibenzofuran group, asubstituted or unsubstituted triphenylene group, a substituted orunsubstituted phenanthrene group, or a substituted or unsubstituteddibenzosilole group.
 18. The organic light emitting device as claimed inclaim 1, wherein: the second hole transport layer includes the fourthhole transport material represented by Formula 4, and the fourth holetransport material includes one of the following Compounds 4-1 to 4-20:


19. The organic light emitting device as claimed in claim 1, wherein thehole transport region further includes a hole injection layer betweenthe anode and the first hole transport layer.
 20. The organic lightemitting device as claimed in claim 1, wherein the electron transportregion includes: an electron transport layer; and an electron injectionlayer on the electron transport layer.